Scanning system with document previewing

ABSTRACT

A document scanning system includes a preview sensor that is dedicated to document previewing and distinct from any other sensor that is involved in the document scanning process. The preview sensor is preferably a two-dimensional sensor array that captures the outline of an entire document in parallel. The captured document outline is previewed on a display device relative to an actual image area that is defined by the scanning system. In an enhanced embodiment of the scanning system, the preview sensor captures an image that is printed on the document in addition to the outline of the document, so that the image of the document is also previewed relative to the image area. Providing a dedicated preview sensor that captures document position and image data in parallel enables real-time display of a document relative to the image area.

CROSS REFERENCE TO RELATED APPLICATION

This is a continuation of application Ser. No. 09/299,690, filed on Apr.26, 1999 now U.S. Pat. No. 6,157,439.

TECHNICAL FIELD

The invention relates to document scanning systems, and moreparticularly to a scanning system that includes document previewing.

BACKGROUND OF THE INVENTION

Copying or scanning a document on a copy or scanning system typicallyinvolves placing a document (either manually or automatically) incontact with an image capture surface. Because most copy machines andscanners accommodate different size documents, the image capture surfaceis usually larger than a typical 8.5 inch×11 inch (215.9 mm×279.4 mm)piece of paper. As a result of the large image capture surface,documents can be placed on the image capture surface in positions thatdo not correspond to the particular location required for copying orscanning, which will be referred to herein as the “image area.”Documents located in the wrong position on the image capture surfaceresult in unacceptable images that are usually discarded, wasting timeand resources.

Properly locating a document on an image capture surface is furthercomplicated when features such as magnification or reduction areutilized. When magnification or reduction features are utilized, it isdifficult to determine exactly how the document fits within the actualimage area, and it is difficult to determine how images on the documentwill appear.

In order to determine the appearance of an image before a scanned imageor a copy is actually generated, it would be advantageous to have asystem that enables document previewing. In conventional photo-copiers,document copying is accomplished by illuminating a document and thendirecting reflected light from the document onto a photosensitive beltor platen. Changes in electrical charge on the photosensitive belt orplaten are then utilized to transfer toner to a new piece of paper.While conventional copiers work well for their intended purpose, they donot include sensing hardware that can be easily utilized for documentpreviewing.

In addition to conventional copiers, systems have been developed thatutilize electronic imaging techniques to copy images from documents.Systems utilizing electronic imaging have been equipped with documentpreviewing capability. Known copy systems with document previewingcapabilities are disclosed in U.S. Pat. No. 4,656,524, entitled“Electronic Imaging Copier,” issued to Norris et al., and U.S. Pat. No.4,656,525, entitled “Electronic Imaging Copier,” issued to Norris. Bothcopiers of Norris utilize a photo responsive device such as a linearcharged coupled device (CCD) array to capture an electronic image of thetarget document. The scanned, electronic image is utilized to print acopy of the target document. The electronic image is captured by passingthe linear CCD array by the document in a line-by-line manner.

Previewing a document with the Norris copiers involves scanning thedocument with a linear CCD array to create electronic image data andthen displaying the electronic image data on a display device. TheNorris copiers utilize the same scanning hardware for documentpreviewing as is used for document copying. While the previewing featureof Norris works well for its intended purpose, previewing a documentutilizing the same scanning hardware as is used for document copyingrequires a line-by-line scan of the document. The mechanical movementsrequired for line-by-line scanning are time consuming and preventreal-time previewing of the target document.

Known preview systems have also been applied in image scanners that areused to create an electronic copy of a document. For example, an imagescanner that includes a preview system is disclosed in U.S. Pat. No.4,837,635, entitled “A Scanning System in which a Portion of a PreviewScan Image of a Picture Displaced on a Screen is Selected and aCorresponding Portion of the Picture is Scanned in a Final Scan,” issuedto Santos and assigned to the assignee of the present invention. InSantos, the scanner can perform either a preview scan or a final scan.The preview scan is simply a lower resolution version of the final scan.Again, the same scanner hardware is utilized to perform the preview scanor the final scan. Whether the scanner is performing a preview scan or afinal scan, the scanner hardware must sweep across the document in aline-by-line manner to capture the electronic image data. Although thepreview system of Santos works well for its intended purpose, the timerequired to scan a document limits the ability to provide real-timepreviewing.

As a result of the drawbacks regarding prior art preview systems, whatis needed is a preview system that can display a document located on animage capture surface without utilizing the document reproductionhardware, and what is needed is a preview system that can display adocument in real-time.

SUMMARY OF THE INVENTION

A document scanning system includes a preview sensor that is dedicatedto document previewing and distinct from any other sensor that isinvolved in the document capture process. In one embodiment, the previewsensor is a two-dimensional sensor array that captures the outline of anentire document using parallel processing. The captured document outlineis previewed on a display device to determine its position relative toan actual image area that is defined by the scanning system. In anenhanced embodiment of the system, the preview sensor captures an imagethat is on the document in addition to the outline of the document, sothat the image of the document is also previewed relative to the imagearea. Providing a dedicated preview sensor that captures documentposition and image data in parallel enables real-time display of adocument relative to the image area.

The document scanning system having the document previewing capabilityincludes an image capture surface (i.e., a document scanning surface), ascanner system, a preview system and a display device. The image capturesurface is preferably a conventional glass platen, as utilized inconventional photocopy machines and conventional document scanners. Theimage capture surface is transparent and provides a surface on which thedesired document is placed for creating paper or electronic copies.Typically, the image capture surface is integrated with a cover thatimproves illumination of a document during copying or scanning.

The document scanning system may include a conventional scanner system,or a hybrid copy system that combines document scanning and printing toproduce document copies. The conventional scanner system includes alight source and a linear photosensor array. In operation, a documentplaced on the image capture surface is illuminated and the linearphotosensor array is scanned across the document to create an electroniccopy of an image. The electronic copy of the image can then be stored inmemory, displayed, printed and/or edited. As described above, knownpreviewing techniques utilize a low resolution scan with the linearphotosensor array to create a preview image.

The hybrid copy system combines electronic scanning and printing to copya document. In the hybrid copy system, the document is scanned to createelectronic image data. The electronic image data is used to drive aprinter, such as a laser printer, to create a copy of the document thatis located on the image capture surface.

Regardless of the type of system that is utilized to make documentcopies, a dedicated preview system is provided that operates in additionto the scanner system. In an embodiment, the preview system is acombination of hardware and software that is independent of the scannersystem. The preview system displays, on the display device, the outlineof a document that is placed on the image capture surface. In oneembodiment, the outline of the document is displayed relative to anoutline of the actual image area of the scanner system. In anotherembodiment, the preview system displays the image of the documentrelative to the actual image area in addition to the display of theoutline of the document relative to the actual image area.

An embodiment of the preview system includes the image capture surface,a light source, optics, a preview sensor, a processing unit, and thedisplay device. The light source provides light to the image capturesurface in order to illuminate a document that is located on the imagecapture surface. The intensity of light required by the light sourcedepends on whether or not the preview system is configured to displaythe outline of a document or the image on the document in addition tothe outline of the document.

The optics preferably include a wide angle lens that enables opticalenergy from the entire image capture surface to be directed to thepreview sensor. The display device is preferably an LCD display devicethat is integrated with the scanner system.

The preview sensor is dedicated to the previewing system and is separatefrom the sensors that are utilized in the scanner system for scanning.In an embodiment, the preview sensor includes a two-dimensionalphotosensor array that can capture an entire image in parallel withoutscanning across the image capture surface. The preview sensor isoperated at a refresh rate of greater than four frames per second, andpreferably greater than twenty-four frames per second, in order todisplay a real-time representation of the document relative to the imagearea. The preview sensor can be fixed with respect to the image capturesurface. However, the sensor may be movable in order to accommodate forfeatures such as enlarging or reducing.

The processing unit is preferably a hardware and software system thatreceives signals from the preview sensor and transforms the signals intodisplay signals that are compatible with the display device. Theprocessing unit can also take into account paper size and magnificationor reduction in order to display a representation of the image area andthe target document on the display device. The processing unit can bededicated to the preview system or the processing unit can be sharedwith the scanner system.

In operation of the preview system, a document is placed on the imagecapture surface and the document is illuminated by the light source.Light reflected from the document is captured by the preview sensor andthe preview sensor transmits image signals to the processing unit. Theprocessing unit generates display signals and a representation of thedocument is displayed on the display device. The representation of thedocument displayed on the display device is shown relative to the imagearea of the scanner system. If the document is moved on the imagecapture surface, then the movement is shown on the display device,preferably in real-time. If the scanner system is programmed to generatea magnified copy of the original document, then a magnified version ofthe document is displayed on the display device relative to the imagearea of the scanner system. Similarly, if the scanner system isprogrammed to generate a reduced copy of the original, then a reducedimage of the original document is displayed on the display devicerelative to the outline of the image area. Once the document issatisfactorily positioned on the image capture surface, as indicated bythe preview system, the scanning system is utilized to generate a copy,either printed or electronic, of the document.

Because the preview system has a dedicated preview sensor, the previewsensor can be a lower resolution two-dimensional sensor array thatcaptures images of the entire document in parallel without having tomechanically scan across the document. Capturing images of an entiredocument in parallel enables the preview system to display an image ofthe document in real-time, or near real-time. Real-time previewingenables a user to quickly preview a document while making subtleadjustments in order to generate a desired copy on the first attempt.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a depiction of a preferred document scanning system withdocument previewing capabilities in accordance with the invention.

FIG. 2 is a depiction of a preferred preview system in accordance withthe invention.

FIG. 3 is a top view of an exemplary document scanning system thatincludes document previewing in accordance with the invention.

FIG. 4 is a depiction of an exemplary document that is printed on 8.5inch by 11 inch (215.9 mm×279.4 mm) paper.

FIG. 5A is a depiction of a document in a standard position on an imagecapture surface.

FIG. 5B is a depiction of the display of the document shown in FIG. 5Arelative to the image area in accordance with the invention.

FIG. 6A is a depiction of a document in a lowered and to the rightposition on an image capture surface.

FIG. 6B is a depiction of the display of the document shown in FIG. 6Arelative to the image area in accordance with the invention.

FIG. 7A is a depiction of a document in a rotated position on an imagecapture surface.

FIG. 7B is a depiction of the display of the document shown in FIG. 7Arelative to the image area in accordance with the invention.

FIG. 8A is a depiction of a document in a standard position on an imagecapture surface.

FIG. 8B is a depiction of the display of an enlarged version of thedocument shown in FIG. 8A relative to the image area in accordance withthe invention.

FIG. 9A is a depiction of a document in a standard position on an imagecapture surface.

FIG. 9B is a depiction of the display of a reduced version of thedocument shown in FIG. 9A relative to the image area in accordance withthe invention.

DETAILED DESCRIPTION

An embodiment of a document scanning system 10 is depicted in FIG. 1.The document scanning system includes an image capture surface 12, ascanner system 14, a preview system 16, and a display device 18. Asshown, the image capture surface may generate a printed copy 20 of adocument, or an electronic copy 22 of a document. The elements of thedocument scanning system are described first, followed by a descriptionof the system operation.

The image capture surface 12 (i.e., document scanning surface) ispreferably a conventional glass platen as utilized in conventionalphotocopy machines and conventional document scanners. The image capturesurface is transparent and provides a surface on which the desireddocument is placed for copying or scanning. Typically, the image capturesurface is integrated with a cover that improves illumination of adocument during copying or scanning. Documents can be manually placed onthe image capture surface, or in systems with automatic documentfeeders, documents can be automatically placed on the image capturesurface.

The scanner system 14 includes a conventional scanner system, or ahybrid copy system that combines document scanning with printing toproduce document copies. The conventional document scanning systemincludes a light source and a linear photosensor array. In operation, adocument located on the image capture surface is illuminated and thelinear photosensor array is scanned across the document to create anelectronic copy of the image that is on the document. Electronic imagedata is collected during scanning in a line-by-line manner, with theresolution of the image depending on the number of lines that arescanned within a given distance during movement in the verticaldirection and the density of pixel information that is generatedrelative to the horizontal direction. Electronic image data representingthe scanned document can readily be stored in memory, displayed,printed, and/or edited.

The hybrid copy system combines electronic scanning and printing to copya document. In the hybrid copy system, a document is scanned to createelectronic image data. Electronic image data is then used to drive aprinter, such as a laser printer, to create a copy of the document thatis located on the image capture surface.

In an embodiment, the preview system 16 is a combination of hardware andsoftware that is substantially separate from the scanner system 14. Thepreview system displays, on the display device 18, the outline of adocument that is placed on the image capture surface 12. In anembodiment, the outline of the document is displayed relative to anoutline of the actual image area of the scanner system. In anotherembodiment, the preview system displays the image of the documentrelative to the actual image area in addition to the outline of thedocument. The display device is preferably an LCD display device that isintegrated with the scanner system, although other types of displaydevices, such as CRT displays, are possible. For example, the displaydevice may be the display device of a personal computer that isconnected to a scanner. The structure of the preview system is describedin more detail with reference to FIGS. 2 and 3, and examples of theoperation of the preview system are described with reference to FIGS. 4through 9. It should be noted that while the detailed descriptionprimarily describes embodiments relating to copy machines,implementation of the invention is also contemplated with scanners andhybrid scanner/copier machines.

Referring to FIG. 2, an embodiment of the preview system 16 includes theimage capture surface 12, a light source 28, optics 30, a preview sensor32, a processing unit 34, and the display device 18. The light sourceprovides light to the image capture surface in order to illuminate adocument that is located on the image capture surface. The intensity oflight required by the light source depends on whether or not the previewsystem is configured to display the outline of a document or the imageon the document in addition to the outline. In an embodiment, the lightsource is preferably dedicated to the preview system, although the lightsource may be shared with the scanner system 14 in some embodiments.

The optics 30 preferably include a wide angle lens that enables opticalenergy from the entire image capture surface to be directed to thepreview sensor 32. In an embodiment, the optics are dedicated to thepreview system 16, although the optics may be shared with the scannersystem 14 in some embodiments. Although optics are utilized in theembodiment, optics are not critical.

The preview sensor 32 may include a two-dimensional photosensor arraythat can capture an entire image up to the size of the image capturesurface 12. Thus, the preview sensor can capture an entire image inparallel without being “scanned” across the image capture surface. Thepreview sensor is dedicated to the previewing system and as shown inFIGS. 1 and 2, the preview sensor is separate from any sensors that areutilized in the scanner system 14 for copying and/or scanning. In oneembodiment, the preview sensor is a CCD array that is operated at arefresh rate of greater than four frames per second, and preferablygreater than twenty-four frames per second, in order to display a“real-time” representation of the document relative to the image area.In one embodiment the preview sensor is fixed with respect to the imagecapture surface. However, in other embodiments, the sensor may move toaccommodate features such as enlarging or reducing.

Typically, the processing unit 34 is a hardware and software system thatreceives signals from the preview sensor 32 and transforms the signalsinto display signals that are compatible with the display device 18. Theprocessing unit may also generate the display signals for the image areaof the scanner system 14. That is, the processing unit takes intoaccount paper size and magnification or reduction, in order to display arepresentation of the image area on the display device. The processingunit can also be configured to support the optics 30 in order to, forexample, provide a higher resolution display of a document image throughelectronic manipulation. The processing unit can be dedicated to thepreview system 16 or the processing unit can be shared with the scannersystem 14.

FIG. 3 is a top view of an exemplary copy system 40 that includesdocument previewing. As described above, the image capture surface 42 isa glass platen upon which a document is placed face down. The displaydevice 44 is preferably an LCD display that is integrated into the topsurface of the copy system. The top surface of the copy system alsoincludes a control panel 46 which is used to operate the copy system. Inaddition, although not shown, the copy system preferably includes acover that fits over the image capture surface in order to improveillumination of documents. The cover may include an automatic documentfeeder that positions documents on the image capture surface. Inembodiments involving document scanners, the display device may not beintegrated into the scanner. For example, the display device may be theCRT monitor of a personal computer.

In operation, a document is placed on the image capture surface 12 ofthe preview system 16 of FIGS. 1 and 2 and the document is illuminatedby the light source 28. Light reflected from the document is directedonto the preview sensor 32 by the optics 30. The preview sensor capturesthe reflected light and generates electrical signals which aretransmitted to the processing unit 34. The processing unit generatesdisplay signals from the electrical signals and a representation of thedocument is displayed on the display device 18. Preferably, the documentis displayed relative to the image area of the associated scanner system14.

FIGS. 4 through 9 are examples that help describe the operation of thepreview system 16 that is integrated into a document scanning system 10as shown in FIGS. 1 through 3. FIG. 4 is a depiction of an exemplarydocument 50 that consists of a standard 8.5 inch by 11 inch (215.9mm×279.4 mm) piece of paper. An “A” is printed approximately in thecenter of the paper. The document shown in FIG. 4 is utilized in FIGS. 5through 9 to describe the operation of the preview system.

Referring to FIG. 5A, the document 50 shown in FIG. 4 is placed on theimage capture surface 42 which is similar to the image capture surfacethat is shown in FIG. 3. Although the A is visible on the document asshown in FIG. 5A for explanation purposes, in most applications the Awill be face down on the image capture surface such that the A, alsoreferred to as the image, is not visible to a user. FIG. 5B is adepiction of the display device 44 as shown in FIG. 3 that includes apreview of the document that is located on the image capture surface asshown in FIG. 5A. The image area 54 within the display device isidentified by the dashed-line box. In the example of FIGS. 5A and 5B,the document is an 8.5 inch by 11 inch piece of paper and the image areashown on the display device represents an 8.5 inch by 11 inch piece ofpaper. If the paper size were changed, the image area would be changedaccordingly. In FIG. 5A, the document is aligned on the image capturesurface in a position that coincides with the image area, and thus inFIG. 5B the document outline 52 is displayed by the preview system asbeing entirely within the image area.

It should be noted that in the examples described with reference toFIGS. 5 through 9, the image on the document 50, in addition to theoutline of the document, is previewed on the display device 44. However,in another embodiment, only the outline of the document is displayedrelative to the image area 54. Displaying only the outline of thedocument would enable the use of a lower resolution preview sensor andless illumination. All of the examples described with reference to FIGS.5 through 9 can be implemented with the document outline only.

FIG. 6A depicts the document 50 in a different position on the imagecapture surface 42. In FIG. 6A, the document is moved down and to theright relative to the image capture surface. FIG. 6B depicts the displayof the document relative to the image area 54. As shown in FIG. 6B, theoutline 52 of the document and the image of the document are shifteddown and to the right relative to the identified image area. If a copyoperation is initiated with the document in the position as shown, onlythe upper left corner of the document would be copied. By displaying theimage of the document relative to the image area utilizing the previewsystem, undesired positioning can be corrected before a copy or scanoperation is initiated.

In an embodiment, the preview system 16 operates in real-time, such thatmotion of the document relative to the image capture surface isdisplayed on the display device. For example, a user can adjust theposition of the document on the image capture surface 12 and 42 whileobtaining realtime feedback until the document is positioned properly.Providing real-time previewing saves time, especially when compared tothe time that would be required to scan the document utilizing thescanner system upon each position change.

FIG. 7A depicts the document 50 after being rotated 90° relative to theposition of the document in FIG. 5A. FIG. 7B depicts the display of therotated document relative to the image area 54. As shown in FIG. 7B, theoutline 52 of the document and the image of the document are rotated 90°relative to the identified image area. Because the image area remains inthe “portrait” layout and because the document is now in the “landscape”layout, portions of the document fall outside of the image area.Initiation of a print operation will print only the portion of thedocument that is within the identified image area.

FIG. 8A depicts the document 50 in the same position as in FIG. 5A,however, the document scanning system has been programmed to enlarge, ormagnify, the document before copying or scanning. FIG. 8B depicts thedisplay of the enlarged document outline 52 and the enlarged documentimage relative to the image area 54. As shown in FIG. 8B, the enlargeddocument outline and the enlarged document image extend beyond the imagearea. If a copy of the document is created with the document positionedas shown in FIG. 8A, some portions of the document image will not beincluded in the copy. In an embodiment, corrections for magnificationare made by the preview system and displayed in real-time so that themagnification can be precisely adjusted before a copy or scan operationis initiated.

FIG. 9A depicts the document 50 in the same position as in FIG. 8A,however, the document scanning system has been programmed to reduce, orshrink, the document before copying or scanning. FIG. 9B depicts thedisplay of the reduced document outline 52 and the reduced documentimage relative to the image area 54. As shown in FIG. 9B, the entiredocument fits within the image area and thus will be included in a copyor scan operation. As with enlargements, changes in the reduction arepreferably displayed in real-time by the preview system. In both casesof enlargement or reduction, motion in the x and y planes of the imagecapture surface is preferably displayed in real-time. In one embodiment,the preview system can be directed to automatically adjust themagnification or reduction of a document and/or an image so that thedocument and/or image utilize the entire image area.

The type of preview sensor 32 utilized in the preview system depends onthe level of display resolution that is desired. For example, a simpleone bit preview sensor array can be used to sense the outline of adocument or to sense the document outline in addition to a lowresolution image. A preview sensor array with higher resolution can beutilized to distinguish levels of grayscale. Color filters can also beutilized to provide color previewing if desired. The preview system canbe configured to allow a user to select the level of resolution and toselect whether only the document outline will be displayed or whetherthe document image will also be displayed.

If the previewing of only the document outline is required, ambientlight may serve as the light source. Utilizing ambient light isappropriate when the cover of the document scanning system is up,exposing the image capture surface.

What is claimed is:
 1. A document scanning system for scanning an imagefrom a document comprising: means for generating an electronic copy ofsaid document image, said electronic copy generating means including adocument scanning surface; and means, in optical contact with saiddocument scanning surface, for previewing a position of said documentrelative to said document scanning surface, said previewing meansincluding an electronic preview sensor that is dedicated to documentpreviewing and a display device that displays said position of saiddocument relative to said document scanning surface in at least partialresponse to electrical signals from said electronic preview sensor, saidelectronic preview sensor including rows and columns of discrete sensorelements.
 2. The document scanning system of claim 1 wherein saidposition previewing means includes means for previewing said documentimage relative to said document scanning surface in addition topreviewing said position of said document.
 3. The document scanningsystem of claim 2 wherein said electronic preview sensor is atwo-dimensional sensor array that generates image information that isresponsive to light reflected from said document, said image informationbeing generated in parallel.
 4. The document scanning system of claim 3wherein said two-dimensional sensor array remains in a fixed positionrelative to said document scanning surface while said image informationis being generated by said two-dimensional sensor array, saidtwo-dimensional sensor array being sufficiently large to generate saidimage information for an entirety of said document while saidtwo-dimensional array remains in said fixed position.
 5. The documentscanning system of claim 2 wherein said document image previewing meansincludes a processing unit that generates image area display signalsrepresenting an outline of an image area on said display device relativeto said document image.
 6. The document scanning system of claim 1wherein said position previewing means includes a processing unit thatgenerates image area display signals that represent an outline of animage area for said electronic copy generating means, said displaysignals being transferred to said display device.
 7. The documentscanning system of claim 1 wherein said electronic copy generating meansis operatively associated with a printing means, said printing meansenabling generation of a copy of said document on a copy medium.
 8. Thedocument scanning system of claim 1 wherein said electronic copygenerating means includes an electronic scanner having a linear sensorarray that is dedicated to image scanning and separate from said previewsensor, wherein said electronic scanner generates an electronic copy ofsaid document image.
 9. A document scanning system for scanning an imagefrom a document comprising: a document scanning surface, said documentscanning surface being transparent such that said document image isvisible through said document scanning surface when said document is incontact with said document scanning surface; a scanner, operativelyassociated with said document scanning surface, said scanner beingenabled to generate an electronic copy of at least a portion of saiddocument image, said scanner having a defined image area associated witheach scan operation, said scanner including a linear photosensor arraythat is mounted to scan said defined image area associated with eachsaid scan operation; and an electronic preview system, operativelyassociated with said document scanning surface, said electronic previewsystem including a dedicated preview sensor connected to receivereflected light from said document and to generate electrical signalsthat are responsive to said reflected light, said electronic previewsystem further including a display device connected such that for eachsaid scan operation said display device receives electrical signals fromsaid scanner that represent said defined image area and receives saidelectrical signals from said dedicated preview sensor that represent aposition of said document relative to said defined image area.
 10. Thedocument scanning system of claim 9 wherein said dedicated electronicpreview sensor is a two-dimensional array of sensor elements thatgenerate image information from said document image, and wherein imagesignals that are responsive to said image information are displayed onsaid display device relative to said defined image area.
 11. Thedocument scanning system of claim 10 wherein said image signals areadjusted by a processing unit to account for magnification or reductionof said document image.
 12. The document scanning system of claim 10wherein said dedicated electronic preview sensor is automaticallyrefreshed at least four times per second, thereby enabling real-timedisplay of said position of said document relative to said defined imagearea.
 13. The document scanning system of claim 10 wherein saiddedicated electronic preview sensor is automatically refreshed at leasttwenty-four times per second, thereby enabling real-time display of saidposition of said document relative to said defined image area.
 14. Thedocument scanning system of claim 10 wherein said defined image area isrelated to the size of paper that is to be utilized for each scanoperation.
 15. The document scanning system of claim 9 wherein saidelectronic preview system includes a light source that is dedicated tosaid electronic preview system and oriented to direct light at saiddocument scanning surface.
 16. The document scanning system of claim 9wherein said electronic preview system includes dedicated preview opticslocated between said document scanning surface and said dedicatedpreview sensor along an optical path of said reflected light.
 17. Thedocument scanning system of claim 9 wherein said electronic previewsystem includes a processing unit connected to receive sensor outputsignals from said dedicated preview sensor and to output preview displaysignals to said display device.
 18. The document scanning system ofclaim 17 wherein said preview display signals are generated by saidprocessing unit in partial response to image magnification or imagereduction.
 19. A system for previewing and scanning a document imagecomprising: a document scanner system having a scanning surface, ascanner sensor and a light source that are utilized to create anelectronic image of said document image when a document containing saiddocument image is located on said scanning surface, said scanner sensorbeing a row of discrete sensor elements which convert light intoelectrical signals, said document scanner system having an image arearepresenting an area on said scanning surface that is scanned in aparticular scanning operation; a document preview system opticallyaligned relative to said scanning surface to detect light therefrom,said document preview system having a dedicated preview sensor that isdistinct from said scanner sensor, preview sensor optics connected todirect light from said document image to said preview sensor, and adisplay device, said dedicated preview sensor including atwo-dimensional sensor array that detects said document image from theentire area of said document, said sensor array including rows andcolumns for discrete sensor elements which convert light into electricalsignals; and means, operatively associated with said document scannersystem and document preview system, for generating display signalsrepresenting a position of said document image relative to said imagearea for said particular scanning operation.
 20. The system of claim 19further including means for refreshing said dedicated preview sensor atleast four times per second.